Math

toFixed() #

• When the toFixed() method is called, you can specify how many decimal places to maintain as an argument.

• It returns a string data type.

const pi = 3.14159265359879
console.log(pi); // 3.14159265358979

const str = pi.toFixed(2);
console.log(str); // 3.14
console.log(typeof str); // Stirng

parseInt() , parseFloat() #

These functions are also global functions.

• parseInt() extracts characters and returns them as an integer type.
• parseFloat() extracts characters and returns them as a float type.

const pi = 3.14159265359879
console.log(pi); // 3.14159265358979

const str = pi.toFixed(2);
console.log(str); // '3.14'
console.log(typeof str); // Stirng

const integer = parseInt(str);
const float = parseFloat(str);

console.log(integer); // 3
console.log(float); // 3.14

Math.abs() #

• abs : absolute - The Math.abs() function returns the absolute value of the given number.

Math.min() , Math.max() #

• min : Returns the smaller value among the given arguments.
• max : Returns the larger value among the given arguments.

Math.ceil() Math.cloor() #

• ceil : Rounds up the given argument to the nearest integer.
• floor : Rounds down the given argument to the nearest integer.

Math.round() #

• Rounds the given argument.

Math.random() #

• Returns a random number.

console.log('abs :', Math.abs(-12)) // abs : 12

console.log('min :' ,Math.min(2,8)) // min : 2

console.log('max :', Math.max(2,8)) // max : 8

console.log('ceil :', Math.ceil(3.14)) // ceil : 4

console.log('floor :', Math.floor(3.14)) // floor : 3

console.log('round :' ,Math.round(3.5)) // round : 4

console.log('random :' ,Math.random()) // 랜덤한 수 0 ~ 1

Let's print a random integer from 1 to 10. #

let rand = Math.floor(Math.random() * 10 + 1);
console.log(rand) // 1 ~ 10

1. Execute the floor() method on the rand variable, and inside it, execute random().

2. Executing random()*10 outputs numbers from 0 to 9, so we add +1. Then, applying floor() to round down will result in random integers from 1 to 10.